Steam control method and apparatus for fabric pressing machine

ABSTRACT

A method for selectively varying the vacuum pressure applied to the buck of a buck and swingable head type fabric pressing machine to establish the optimum vacuum pressure in accord with the weight and drying characteristics of the fabric to be pressed to assure effective drying and setting of the press in the fabric and a vacuum valve for presetting the vacuum pressure to the optimum value by adjustably venting the valve to the atmosphere. The valve is characterized by a vacuum line coupling means that may be removed from the valve without breaking the line connection to gain access to the valve biasing spring means, the valve, and valve seat for the purpose of servicing and replacement.

United States Patent 11 1 Gerod June 12, 1973 [5 STEAM CONTROL METHOD AND 2,919,507 1/1960 Goldman 38/36 P T S FOR FABRIC PRESSING 9/1967 Pyke et al. 38/144 MACHINE Primary Examiner-Robert G. Nilson 76 Inventor: John T. Gerod 312 N. Lmcoln 1 Avenue, Scranton Pa 8504 AttorneyStrauch, Nolan, Neale, N1es & Kurz 22 Filed: Se t. 21 1970 l 1 p 57 ABSTRACT [21] Appl. No.: 73,775

. A method for select1vely varying the vacuum pressure applied to the buck of a buck and swingable head type 417/440, fabric pressing machine to establish the optimum vac- 251/129 uum pressure in accord with the weight and drying [5 CL characteristics of the fabric to be pressed to assure ef. Fleld Of Search fective and setting the press in the fabric and 604, 1310- 3; 417/306, 440 a vacuum valve for presetting the vacuum pressure to the optimum value by adjustably venting the valve to References Clted the atmosphere. The valve is characterized by a vac- UNITED STATES PATENTS uum line coupling means that may be removed from 3,322,151 5/1967 Giese et a1 137/604 x the valve Without breaking the line Connection to gain 1,308,112 7/1919 Raver 137/606 access to the valve biasing p g means, the valve, d 2,134,767 11/1938 Strancke 137/606 X valve seat for the purpose of servicing and replace- 2,347,196 4/1944 Hulman et al. 417/306 X ment, 3,517,691 6/1970 Kilgore 137/606 X 2,703,939 3/1955 Clarke 38/41 5 Claims, 5 Drawing Figures so 55 i 63 5e 42-f- 1==== 489 X 48 SHEEIIEQ wEmzmQzoo PAIENIED JUN 1 2 B75 INVENTOR JOHN T. GEROD WW ATTORNEYS PAINTED- 3.738.385

INVENTOR JOHN T. GEROD ATTORN 5 STEAM CONTROL METHOD AND APPARATUS FOR FABRIC PRESSING MACHINE BACKGROUND OF INVENTION In the commercial pressing of fabrics and garments, it is customary to employ steam pressing machines of the type having pressing elements generally identified as the buck and the head. A typical machine of this type is shown in US. Pat. No. l,66l,l53 issued Mar. 6, 1928, to Herbert G. Beede. In such machines the buck is fixedly mounted on a stationary support frame and the head is hingedly mounted on the support frame to swing about an axis parallel to the longitudinal axis of the buck between a pressing position in superposed mating engagement with the buck and a nonpressing position spaced upwardly from the buck. Suitable foot treadles and linkage arrangements are conventionally provided to swing the head between its pressing and non-pressing positions and both the buck and head comprise hollow, elongated, metal bodies matingly tapered from one end to the other end, both ends being rounded. The upper face of the buck is formed by a perforated plate of convex cross-section and the mating face of the head is formed by a perforated plate of concave cross-section. Both mating faces are covered by foraminous padding or the like drawn smoothly over their respective opposed surfaces and secured in conventional manner under peripheral flanges to form steam emitting pressing faces for engaging the opposite sides of the fabric or garment to be pressed.

The buck and head are respectively separated into a heating chamber and a steam emitting chamber immediately adjacent their respective perforated plates and dry steam at about 80 pounds per square inch pressure is continuously passed through the heating chambers to maintain the buck and head at operating temperature. Suitable piping fitted with a manually actuated main control valve, usually foot operated, is provided to selectively bypass or supply dry steam from the heating chambers to the steam emitting chambers when the head is brought into its pressing position relative to the buck. The condensation forming in the head and buck is conventionally removedthrough condensate return lines containing serially connected check valves and leading to the steam generator to assure a supply of dry steam at all times and prevent the formation of wet steam which will not guarantee the desired pressing effect. The selectively bypassed steam passes successively through the perforated plates and their respective padded surfaces to the fabric or garment being pressed to steam and shape the fabric or garment and setting of the shape to the desired pressed shaped is accomplished by appropriate drying conventionally effected by supplying dry steam through the head while connecting the lowest point of the buck through a valved vacuum line connected to a vacuum pump to remove the condensate collecting in the padded surfaces and the fabric or garment being pressed. Prior to this invention, the vacuum line valve has been merely a conventional type two way diaphragm valve which is either completely closed or completely opened.

It has been determined that proper drying and setting is essential to assure a proper pressing effect and that different fabrics or garments made from different mate rials necessitate differing drying rates to produce the desired set. The present invention is directed to a novel drying method and vacuum line valve therefore which will assure a proper drying of the many differing fabrics marketed today.

SUMMARY OF THE INVENTION It, accordingly, is a primary object of this invention to provide a novel method of varying the drying rate of conventional steam pressing machines by controlling the vacuum pressure applied to the buck during the drying operation.

Still another object of the present invention is to provide a valve of the diaphragm type having a valved outlet to the atmosphere adapted to be preset to bleed varying amounts of ambient air into the vacuum line to retard the rate of steam passage through the fabric or garment being pressed and the consequent removal of the resulting condensate from the padded surfaces and the fabric or garment in accord with the weight and texture of the fabric or garment.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects will appear from the following description and appended claims when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagrammatic illustration of the buck and head of a conventional steam pressing machine, the steam and condensate return lines provided therefore, and the conventional vacuum line fitted with the novel vacuum valve of the present invention;

FIG. 2 is an enlarged left end elevational view of the novel vacuum valve of FIG. 1;

FIG. 3 is a right side view of the valve of FIG. 2 with the right end there broken away along a chordal plane through the condensate return line connection;

FIG. 4 is a longitudinal section through the valve of FIG. 2 taken substantially on line 4-4 looking in the direction of the arrows; and

FIG. 5 is a longitudinal sectional view of a simple vacuum vent pipe section which may be installed in existing pressing machine vacuum lines to convert them to the method of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With continued reference to the drawings wherein like reference numerals are employed throughout to indicate the same parts and particularly to FIG. 1, a conventionally constructed pressing machine of the general type shown in the aforementioned US. Pat. No. 1,661,153 is diagrammatically illustrated. It comprises a stationary buck l0 and swingable head 11 supported conventionally by linkage (not shown) to swing downwardly from its illustrated non-pressing position into pressing position with its underside in full covering engagement with the upperside of buck 10. Steam inlet lines 12 and 13, supplied with dry steam at about lbs. pressure from a common supply line 14 connected to a'steam generator (not shown) and provided with a shut-off valve 15 normally opened during pressing operations to continuously supply steam to the heating chambers 22 of buck l0 and head 11 to maintain the metal chamber walls at operating temperature to condition the machine for pressing operations. This maintained heating minimizes condensation which is removed from chambers 22 through condensate return lines 16 and 17 serially connected to a common condensate return line 18 at a point between shut-off valve 19 connected in line 18 and a check valve 20 interposed between the adjacent ends of lines 17 and 18. Line 18 beyond valve 19 is conventionally connected to the steam generator (not shown) to return the removed condensate to the generator.

Buck and head 11 are conventionally divided by metal partition walls 21 to separate heating chambers 22 from opposed steam emitting chambers 23, the opposing faces of which are formed by respective perforated plates 25 and 26 overlaid by foraminous padding 27 and 28 which form the pressing surfaces contacting the fabric or garment to be pressed. Bypass valves 24 mounted inside of buck 10 and head 11 on partition walls 21 and conventionally connected for operation by respective foot treadles (not shown) are provided to bypass dry steam from heating chambers 22 to steam emitting chambers 23 during the pressing operation as will be presently described.

The plate members 25 and 26 are conventionally respectively of convex configuration in cross-section and mating concave configuration in cross-section and the padding 27 and 28 conforms in cross-sectional configuration to the respective plates to provide mating convex and concave pressing surfaces.

The partition wall 21 of buck 10 adjacent one end (the right end in FIG. 1) is depressed and formed to provide a suction channel and outlet 29 connected through vacuum line 31 and the manually operated normally closed solenoid valve 32, provided by this invention to replace the conventional fully closed-fully open solenoid operated vacuum valve of the prior art pressing machines, to a condensate accumulator tank 33 and vacuum pump 34 exhausting through line 35 to the atmosphere. Pump 34 is driven by an electric motor 36 in conventional manner.

The pressing machine of the present invention is conventionally operated to provide the initial steaming function. Such operation consists in smoothing the fabric or garment to be pressed over the padding 27 of buck l0 and actuating a foot pedal (not shown) to swing head 1 l downwardly into pressing position to engage the fabric or garment between the opposed padded faces of buck l0 and head 11. While maintaining head 11 in its pressing position the conventional foot treadles controlling bypass valves 24 are actuated simultaneously or selectively in customary manner to bypass dry steam under pressure from chambers 22 to steam emitting chambers 23. This bypassed steam passes outwardly in opposite directions through perforated plates 21 and the respective foraminous paddings 27 and 28 to the opposite surface of the fabric or garment being pressed to steam the fabric or garment which then conforms closely to the contour of the mating padding surfaces. This steaming and pressing operation, usually accomplished in a matter of seconds, removes all wrinkles that are present and moistens and shapes the portion of the fabric or garment exposed to the steam.

It then becomes essential to dry the pressed fabric or garment to set the wrinkle free shaped portion disposed between buck l0 and head 11. This drying operation, effected by supplying dry steam through head 11 while the buck is connected to the vacuum line to draw the supplied dry steam and ambient air through the steamed garment or fabric and into buck 10, is a most critical and important step, equally important as the pressing operation, since it sets the press in the fabric or garment and assures the desired finished quality and appearance. In the pressing of light materials, such as polyesters and the like, or a too rapid drying of any materials effected with too high a vacuum, an excessive amount of ambient air is sucked through the steamed fabric or garment into the buck 10 resulting in a cooling effect producing excessive amounts of condensation. This resulting excessive condensation moistens the fabric or garment and the padding 27 destroying the desired pressing and forming quality of the pressing operation, causes the fabric or garment to adhere to the padding 27 preventing easy removal of the fabric or garment from buck l0, and effects a cooling of the metal of the buck below the temperature required to assure the desired quality of the press. Avoidance of these problems using the fully closed-fully open vacuum valves of the prior art can only be avoided by extreme expertise of the operator, seldom obtainable by the many existing commercial pressing establishments.

Applicant has solved these problems by modifying the prior art pressing method by varying the applied vacuum pressure in accord with the varying weight and drying characteristics of the fabric or garment being pressed. Thus, if the article being pressed is a light weight, fast drying material, such as a polyester fabric, the vacuum pressure applied is reduced to assure a lesser volume of dry steam and air passing through the fabric or garment and padding 27 and a reduced cooling effect. If the article being pressed is a heavy wool garment or a lined fabric the vacuum pressure is increased to its maximum value or a point sufficiently below maximum value to assure proper drying and setting of the press. Since the optimum vacuum pressure for materials of varying weight and lined or unlined articles may differ widely over a range between the maximum available pressure and a vacuum pressure approximately equal to the pound pressure of the supplied dry steam, it is contemplated that the optimum vacuum pressure be determined empirically. It is further contemplated that commercial establishments having relatively large quantities of articles of similar material in different weights and of different drying characteristics will sort the articles to be pressed into piles of like or similar character so the like or similar articles may all be pressed at the same setting of the vacuum pressure. This practice will avoid the necessity of resetting the vacuum pressure for each article as it is reached for pressing and, therefore, increase the overall output of the machine to produce a high quality finished product.

In order to effectively practice applicants modified method, the vacuum valve 32 of the present invention is constructed with a main elongated valve body 41 of hexagonal configuration formed at one end with an enlarged cylindrical chamber 42 opening through the end, an adjacent, coaxially arranged, cylindrical chamber 43 of reduced diameter defining an annular shoulder 44 at the line of juncture of chambers 42 and 43 and on wall 45 at the opposite end provided with a through coaxially arranged bore 46. One flat wall of body 41 adjacent the one end is formed with a radially directed boss 47 having an axially directed, slot-like, through air passage 48 intersecting chamber 42 and a right angularly directed cylindrical through bore 49 for a purpose to be presently pointed out. This same flat wall in axially spaced relation along body 41 is provided with a cylindrical threaded through bore 51 intersecting chamber 43 beyond shoulder 44 and adapted to threadedly receive the threaded end of the run of vacuum line 31 leading to condensate accumulator tank 33. The opposite flat wall in coaxial, diametrically opposed relation to bore 51 is provided with a cylindrical through bore 52 of substantially smaller diameter adapted to mount a pressure gauge 50 for registering the effective vacuum pressure applied to buck 10.

Shoulder 44 is counterbored at 53 to form an annular recess which receives in press fitted relation an annular valve seat 54 which projects forwardly into chamber 42 to form a seat for a disc-like valve member 55. Valve member 55 is fixedly mounted on the threaded end 56 of an elongated valve stem 57 by a pair of adjustable clamp nuts 60. Stem 57 extends axially through chamber 43 and a combined sleeve bearing and seal 58 pressed fitted in end wall bore 46. The end of stem 57 remote from threaded end 56 projects outwardly from sleeve bearing 58 into end butted engagement with the reduced diameter end 59 of a cylindrical headed armature 61 of a normally deenergized solenoid actuator 62 of conventional construction fixedly mounted on body end wall 45. Solenoid actuator 62 is conventionally wired to a vacuum valve control pedal (not shown) of the type heretofore provided for actuating the fullyclosed, fully-opened vacuum valve provided on the prior art pressing machines.

Valve member 55 is normally biased to its closed position illustrated in FIG. 4 by a tapered biasing spring 63 the smaller end of which seats on valve disc 55 in surrounding relation to the outer clamp nut 60 and its washer 64 which serve to retain the smaller end of spring 63 against undue lateral shifting movement relative to valve disc 55. The opposite end of biasing spring 63 seats on the diametrically opposed spokes 65 of a spring retainer ring 66 dimensioned to closely but freely enter chamber 42. Ring 66 is held against axial outward disassociation from chamber 42 by abutting engagement with the end face of the reduced diameter end 67 of a hexagonally shaped coupling member 68 secured to the one end of body member 41 by a pair of diametrically opposed Allen headed screws 69 threaded into suitably tapped apertures formed in the one end face of body member 41. Coupling member 68 has a coaxially arranged through bore 71 suitably tapped to threadedly receive the run of vacuum line 31 which connects to outlet 29 of partition wall 21 of buck 10.

Referring to FIG. 4, it will be appreciated that the above described vacuum valve structure provides a valve which may be readily disassembled for servicing of valve seat 54, valve disc 55 and spring 63 and its retainer ring 64 merely by removing securing screws 69 to free coupling member 68 with vacuum line 31 attached for axial shifting movement relative to valve body 41 to withdraw the short reduced diameter end 67 from the end of chamber 42. Likewise, the solenoid actuator 62 mounted on valve body end wall 45 is fully exposed for removal and servicing without disturbing the connections of the vacuum valve and vacuum line 31.

The annular bore 49 of boss 47 of valve body 41 rotatably mounts in close rotating fit the body 71 of a plug type throttling valve 72 having a through slot passage 48a dimensioned to mate with slot 48 and a knurled head 73 adapted to be grasped by hand to rotate valve 72 and increase or decrease the inflow of ambient air through passage 48 under influence of the vacuum applied to chamber 42 when valve disc 55 is unseated by energization of solenoid actuator 62. Valve 72 is retained against axial withdrawal from bore 49 by a headed screw 74 threaded into a suitably tapped bore in the lower end of body 71. The throttling of the inflow of air through passage 48 into chamber 42 varies the effective vacuum pressure applied to buck 10 during the drying and setting operation. By suitable positioning of throttling valve 72 to admit more or less or no ambient air to enter through passage 48, the full vacuum pressure applied to buck 10 can be provided when required and the vacuum pressure can be readily reduced to any pressure to zero, when required, to properly effect drying and setting of the press in the articles being pressed. Once the optimum drying effect for a particular class of articles is empirically determined, gauge 50 may be read and the reading can be recorded opposite a description of the articles on a record sheet fixed to the pressing machine to provide a ready reference for a future setting of throttle valve 72 for effectively drying and setting the press for like articles.

It will be appreciated from the preceeding description that applicant has provided an extremely effective and simple method and apparatus by which a pressing machine may be preset by even inexperienced operators properly instructed and supervised to assure a high quality pressed finish of articles of varying weight and drying characteristics. It will be further appreciated that the apparatus required to practice applicants improved method, namely, the novel vacuum valve, may be readily substituted for the existing prior art vacuum valve of existing pressing machines without the need of changing any of the controls or existing steam and vacuum lines and accessories since the same controls and steam and vacuum lines are still used.

CONVERSION VALVE EMBODIMENT tional on-off solenoid operated vacuum valve. As will be clear from FIG. 5, valve 32a comprises a main hexagonal body 81 having aligned, tapped bores 82, 83 at its opposite ends in communication with the opposite ends of a cylindrical chamber 42a corresponding to chamber 42 of valve 32. One flat wall of body 81 is formed with a radially directed boss 47a identical to boss 47 of the preferred embodiment of this invention provided with an axially directed, slot-like, through air passage 48 intersecting chamber 42a midway between its ends and a right angularly directed cylindrical through bore 49. Through bore' 49, like through bore 49 of the previous embodiment, rotatably mounts in close rotating fit the body 71 of a plug type throttling valve identical to throttling valve 72 of the preferred embodiment of this invention. Body 71 has a through slot passage 48a operative upon rotation of body 71 to increase or decrease the inflow of ambient air through passage 48 under influence of the vacuum applied to chamber 42a when the conventional on-off solenoid operated vacuum valve is unseated by energization of its solenoid actuator. Valve 32a may most conveniently be introduced into the existing vacuum line by fitting the upstream portion of vacuum line 31 into one tapped bore, for example bore 82, and fitting a conventional pipe union 84 to bore 83 using respective pipe nipples 85 for connecting the union to bore 83 and the tapped bore (not shown) of the conventional solenoid operated vacuum valve.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered inall respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. Vacuum line valving adapting the vacuum line of conventional pressing machines of the buck and head type to vary the applied vacuum comprising a conventional on-off solenoid actuated valve for applying a negative pressure to the buck during drying and setting of the press in a fabric being pressed and a presettable throttling valve venting the vacuum line to the atmosphere to preselect the optimum vacuum pressure applied to the buck determined by the weight and drying characteristics of the fabric and comprising a valve body having coaxially aligned, tapped, inlet and outlet ports communicating with the opposite ends of a common body chamber and adapted to be connected in the vacuum line and an angular directed boss having an axially directed vent passage leading from said common chamber to the ambient atmosphere and a cross passage intersecting said vent passage between its ends and a plug valve fitted to said cross passage and having a through passage disposed to cooperate with said vent passage and upon rotation of said plug valve to vary the flow of ambient air from the atmosphere to said common chamber to establish the optimum vacuum pressure.

2. The vacuum valve of claim 1 wherein said coupling means comprises a main body portion dimensioned to closely fit the open end of said first chamber and provided with said through tapped inlet port and a peripherally continuous flange dimensioned to overly the end of said valvebody defining the open end of said first chamber, said flange and said end of said valve body are respectively provided with diametrically opposed screw passages and tapped screw passages, and securing screws having shanks freely passing through said screw passages and threaded into said tapped screw passages are provided to secure said coupling means to said valve body thereby providing a coupling means which can be readily removed from said valve body without breaking the line connection to gain access to said spring biasing means, said disc valve means and said valve seat for servicing and replacement.

3. Vacuum line valving adapting the vacuum line of conventional pressing machines of the buck and head type to vary the applied vacuum comprising an on-off vacuum line valve means for applying a negative pressure to the buck during drying and setting of the press in a fabric being pressed and a presettable throttling valve venting the vacuum line to the atmosphere to preselect the optimum vacuum pressure applied to the buck determined by the weight and drying characteristics of the fabric wherein said vacuum line valve means comprises a unitary assembly comprising an elongated valve body defining first and second coaxially related, end communicating chambers, said second chamber being of lesser diameter than said first chamber and forming an axially facing valve seat at the communicating chamber ends and having a body end wall at its opposite end provided with a coaxially related through passage for passage of a valve stem therethrough and an angularly related, tapped outlet port intersecting its side wall, and adapting said vacuum line valve means for connection to a vacuum pump, said first chamber opening through the other body end to provide an inlet port adapting said vacuum line valve means for connection to the buck of the pressing machine and having an angularly related passage intersecting its side wall to vent said first chamber to the atmosphere; disc valve means disposed in said first chamber including a valve stem extending axially of said chambers through said body end wall passage and beyond said body end wall for slidably and sealingly supporting said disc valve means for movement toward and away from said axially facing valve seat to control the passage of fluid between said chambers; coupling means fixed to said other body end including a through tapped inlet port coaxially related to said first chamber; a solenoid actuator fixed to said body end wall including a reciprocable armature disposed in end butted relation to the protruding end of said valve stem and operable upon energization of said actuator. to shift said disc valve means away from said valve seat; spring biasing means disposed in said first chamber with its opposite ends engaging the opposing ends of said disc valve means and said coupling means for normally biasing said disc valve means into sealing contact with said axially facing valve seat; and throttling valve means operably associated with said vent passage to vary the opening of said vent passage between fully closed and fully open positions, said throttling valve means including an actuating member disposed for manual operation adapting said throttling valve means for presetting to a preselected position for establishing an optimum vacuum pressure to be applied to the buck of the pressing machine when the solenoid is energized to effect drying and setting of the press in fabrics being pressed on the pressing machine.

4. The vacuum valve of claim 3 wherein said second chamber is provided with a second angularly related, tapped port intersecting its side wall and a pressure gauge is mounted in said second angularly related, tapped port to indicate the vacuum pressure present when said disc valve means is open to enable the throttling valve means to be set to establish the optimum vacuum pressure desired.

5. The vacuum valve of claim 3 wherein said throttling valve means comprises a through cross passage of generally cylindrical cross section intersecting said vent passage between its opposite ends and a plug valve having a body fitting said cross passage and provided with a diametrical through passage shaped and dimensioned to coincide with said vent passage, an actuating stem at one end protruding outwardly from said valve body in position to be grasped by the operator for actuation of said throttling valve, and a head screw threaded into its other end with the head of the screw overlying the portion of the valve body defining the cross passage at said other end to retain said plug valve against axial shifting movement when said actuating stem is grasped for operating said plug valve. 

1. Vacuum line valving adapting the vacuum line of conventional pressing machines of the buck and head type to vary the applied vacuum comprising a conventional on-off solenoid actuated valve for applying a negative pressure to the buck during drying and setting of the press in a fabric being pressed and a presettable throttling valve venting the vacuum line to the atmosphere to preselect the optimum vacuum pressure applied to the buck determined by the weight and drying characteristics of the fabric and comprising a valve body having coaxially aligned, tapped, inlet and outlet ports communicating with the opposite ends of a common body chamber and adapted to be connected in the vacuum line and an angular directed boss having an axially directed vent passage leading from said common chamber to the ambient atmosphere and a cross passage intersecting said vent passage between its ends and a plug valve fitted to said cross passage and having a through passage disposed to cooperate with said vent passage and upon rotation of said plug valve to vary the flow of ambient air from the atmosphere to said common chamber to establish the optimum vacuum pressure.
 2. The vacuum valve of claim 1 wherein said coupling means comprises a main body portion dimensiOned to closely fit the open end of said first chamber and provided with said through tapped inlet port and a peripherally continuous flange dimensioned to overly the end of said valve body defining the open end of said first chamber, said flange and said end of said valve body are respectively provided with diametrically opposed screw passages and tapped screw passages, and securing screws having shanks freely passing through said screw passages and threaded into said tapped screw passages are provided to secure said coupling means to said valve body thereby providing a coupling means which can be readily removed from said valve body without breaking the line connection to gain access to said spring biasing means, said disc valve means and said valve seat for servicing and replacement.
 3. Vacuum line valving adapting the vacuum line of conventional pressing machines of the buck and head type to vary the applied vacuum comprising an on-off vacuum line valve means for applying a negative pressure to the buck during drying and setting of the press in a fabric being pressed and a presettable throttling valve venting the vacuum line to the atmosphere to preselect the optimum vacuum pressure applied to the buck determined by the weight and drying characteristics of the fabric wherein said vacuum line valve means comprises a unitary assembly comprising an elongated valve body defining first and second coaxially related, end communicating chambers, said second chamber being of lesser diameter than said first chamber and forming an axially facing valve seat at the communicating chamber ends and having a body end wall at its opposite end provided with a coaxially related through passage for passage of a valve stem therethrough and an angularly related, tapped outlet port intersecting its side wall, and adapting said vacuum line valve means for connection to a vacuum pump, said first chamber opening through the other body end to provide an inlet port adapting said vacuum line valve means for connection to the buck of the pressing machine and having an angularly related passage intersecting its side wall to vent said first chamber to the atmosphere; disc valve means disposed in said first chamber including a valve stem extending axially of said chambers through said body end wall passage and beyond said body end wall for slidably and sealingly supporting said disc valve means for movement toward and away from said axially facing valve seat to control the passage of fluid between said chambers; coupling means fixed to said other body end including a through tapped inlet port coaxially related to said first chamber; a solenoid actuator fixed to said body end wall including a reciprocable armature disposed in end butted relation to the protruding end of said valve stem and operable upon energization of said actuator to shift said disc valve means away from said valve seat; spring biasing means disposed in said first chamber with its opposite ends engaging the opposing ends of said disc valve means and said coupling means for normally biasing said disc valve means into sealing contact with said axially facing valve seat; and throttling valve means operably associated with said vent passage to vary the opening of said vent passage between fully closed and fully open positions, said throttling valve means including an actuating member disposed for manual operation adapting said throttling valve means for presetting to a preselected position for establishing an optimum vacuum pressure to be applied to the buck of the pressing machine when the solenoid is energized to effect drying and setting of the press in fabrics being pressed on the pressing machine.
 4. The vacuum valve of claim 3 wherein said second chamber is provided with a second angularly related, tapped port intersecting its side wall and a pressure gauge is mounted in said second angularly related, tapped port to indicate the vacuum pressure present when said disc valve means is open to enable the throttling valve means to be set to establish the optimum vacuum pressure desired.
 5. The vacuum valve of claim 3 wherein said throttling valve means comprises a through cross passage of generally cylindrical cross section intersecting said vent passage between its opposite ends and a plug valve having a body fitting said cross passage and provided with a diametrical through passage shaped and dimensioned to coincide with said vent passage, an actuating stem at one end protruding outwardly from said valve body in position to be grasped by the operator for actuation of said throttling valve, and a head screw threaded into its other end with the head of the screw overlying the portion of the valve body defining the cross passage at said other end to retain said plug valve against axial shifting movement when said actuating stem is grasped for operating said plug valve. 